neshacker/nespi

An NES implementation of the Pi-Spigot Algorithm

NesPi

An NES implementation of the "Pi Spigot" algorithm by Stanley Rabinowitz and Stan Wagon. I cover various aspects of the implementation in the NES Pi video on YouTube.

Building

The project requires ca65 and make and can be built by running make from the project root.

NTSC Note

In order to fit 960 digits, the game uses nametable realestate that's usually clipped when running on an NTSC screen. This means if you run it on actual hardware or in some emulators, the digits on the top and bottom may be cut off.

License

MIT

nespi's Issues

Missing directory breaks build

When running make after a fresh clone I see the following error:

Fatal error: Cannot open output file './build/nes-pi.o': No such file or directory

Manually creating a build directory or running make clean solves the problem. My make skills aren't sharp enough to submit a PR which isn't a kludge but I'm sure @rsandor or a fellow Patron can cleanly introduce a dependency which automatically creates that directory using mkdir -p build.

First line cut off on MiSTer

I gave your ROM a test on my MiSTer FPGA setup with the latest core as of this writing. I thought it wasn't working at first, but it is in fact starting the digits off the top of the screen, even on CRT with my underscan setting on.

The core should be fairly accurate, but I am curious on your thoughts on where the fault is.

Note that this is designed to run as a PAL region game

Hey! Thanks for the great videos and including this more complex example for all of us to play with.

When I was getting it up and running, I launched the ROM in FCEUX and thought I had broken something once I got to the Pi-calculation screen. It turns out I had FCEUX's region set to NTSC instead of PAL and it was generating the first line of Pi outside the bounds of the NTSC screen.

I'm not sure if there's a way to specify the region in an NES rom (that sounds like something Nintendo wouldn't have been worried about back then), but it may help others to add a note to the README saying that the built .nes rom should be run in an emulator set to the PAL region.